Display device with touch detection function, touch detection device, and electronic unit

ABSTRACT

A display device with a touch detection function including a plurality of touch detection electrodes arranged in parallel to extend in one direction, formed with a predetermined electrode pattern including an electrode portion and aperture portions, and each outputting a detection signal based on a change of an electrostatic capacitance in response to an external proximity object, a plurality of display elements formed in a layer different from a layer provided with the touch detection electrodes, and arranged by a predetermined number in a width direction in a region corresponding to the touch detection electrode, and a plurality of dummy electrodes arranged in an inter-detection-electrode region of the plurality of touch detection electrodes. The aperture portions are provided to allow an arrangement area ratio of the touch detection electrode to be almost equal to an arrangement area ratio of the dummy electrodes in the inter-detection-electrode region.

RELATED APPLICATION DATA

This application is a continuation of U.S. patent application Ser. No.14/732,066 filed Jun. 5, 2015, which is a continuation of U.S. patentapplication Ser. No. 13/211,393, filed Aug. 17, 2011, now U.S. Pat. No.9,081,447 issued Jul. 14, 2015, the entireties of which are incorporatedherein by reference to the extent permitted by law. The presentapplication claims the benefit of priority to Japanese PatentApplication No. JP 2010-186197, filed on Aug. 23, 2010 in the JapanPatent Office, the entirety of which is incorporated by reference hereinto the extent permitted by law.

BACKGROUND

This disclosure relates to a touch detection device, in particular, to atouch detection device detecting touch events based on a change of anelectrostatic capacitance in response to an external proximity object, adisplay device with a touch detection function including such a touchdetection device, and an electronic unit.

In recent years, a display device capable of inputting information bymounting a contact detection device, which is a so-called touch panel,on a display device such as a liquid crystal display device, orintegrating the touch panel and the display device, and displayingvarious button images and the like on the display device instead oftypical mechanical buttons has attracted attention. The display deviceincluding such a touch panel does not require input devices such as akeyboard, a mouse, and a keypad, and therefore there is a tendency toexpand the use of such a display device to portable informationterminals such as mobile phones, in addition to computers.

Some methods are included in the touch detection methods, and one ofthem is an electrostatic capacitance method. For example, JapaneseUnexamined Patent Application Publication No. 2008-129708 discloses atouch panel including a plurality of X-direction electrodes and aplurality of Y-direction electrodes arranged to face the X-directionelectrodes, and detecting touch events by using a change of anelectrostatic capacitance formed in the intersections of the X-directionelectrodes and the Y-direction electrodes in response to an externalproximity object. These electrodes are formed of a translucent material,however, light transmittance is different between a portion with theelectrode and a portion without the electrode, and therefore, theseelectrodes are possibly viewed from outside. Accordingly, in the touchpanel, dummy electrodes are provided between the X-direction electrodes,or between the Y-direction electrodes to reduce the difference of thelight transmittance between the electrode region formed with theX-direction electrodes and the Y-direction electrodes and theinter-electrode region arranged with the dummy electrodes, and thereforethe X-direction electrodes and Y-direction electrodes are allowed to behardly viewed from outside.

SUMMARY

The X-direction electrodes and the Y-direction electrodes are possiblyviewed due to not only the above-described light transmission but also,for example, reflection of light incident from outside by theelectrodes. However, in Japanese Unexamined Patent ApplicationPublication No. 2008-129708, no description is made as for thereflection. When the X-direction electrodes and the Y-directionelectrodes are viewed due to the reflection, visibility of a screendisplayed on the display device is possibly lowered.

It is desirable to provide a display device with a touch detectionfunction, a touch detection device, and an electronic unit which arecapable of suppressing degradation of visibility of a display screen dueto an electrode, even in a case where light enters from outside.

A first display device with a touch detection function according to anembodiment of the disclosure includes a plurality of touch detectionelectrodes, a plurality of display elements, and a plurality of dummyelectrodes. The plurality of touch detection electrodes is arranged inparallel to extend in one direction, is formed with a predeterminedelectrode pattern including an electrode portion and aperture portions,and each outputs a detection signal based on a change of anelectrostatic capacitance in response to an external proximity object.The plurality of display elements is formed in a layer different from alayer provided with the touch detection electrodes, and is arranged by apredetermined number in a width direction in a region corresponding tothe touch detection electrode. The plurality of dummy electrodes isarranged in an inter-detection-electrode region of the plurality oftouch detection electrodes. The aperture portions are provided to allowan arrangement area ratio of the touch detection electrode to be almostequal to an arrangement area ratio of the dummy electrodes in theinter-detection-electrode region. Herein, the phrase “provided to bealmost equal” or “provided to be almost the same” means that both areprovided to be close to each other as much as possible, even if both arenot completely the same.

A second display device with a touch detection function according to anembodiment of the disclosure includes a plurality of touch detectionelectrodes, a plurality of display elements, and a plurality of dummyelectrodes. The plurality of touch detection electrodes is arranged inparallel to extend in one direction, is formed with a predeterminedelectrode pattern including an electrode portion and aperture portions,and each outputs a detection signal based on a change of anelectrostatic capacitance in response to an external proximity object.The plurality of display elements is formed in a layer different from alayer provided with the touch detection electrodes, and is arranged by apredetermined number in a width direction in a region corresponding tothe touch detection electrode. The plurality of dummy electrodes isarranged in an inter-detection-electrode region of the plurality oftouch detection electrodes. The aperture portions are arranged to allowa total length of all sides of the aperture portions per unit area to bealmost equal to a total length of all sides of the dummy electrode perunit area.

A touch detection device according to an embodiment of the disclosureincludes a plurality of touch detection electrodes and a plurality ofdummy electrodes. The plurality of touch detection electrodes isarranged in parallel to extend in one direction, is formed with apredetermined electrode pattern including an electrode portion andaperture portions, and each outputs a detection signal based on a changeof an electrostatic capacitance in response to an external proximityobject. The plurality of dummy electrodes is arranged in aninter-detection-electrode region of the plurality of touch detectionelectrodes. The aperture portions are provided to allow an arrangementarea ratio of the touch detection electrode to be almost equal to anarrangement area ratio of the dummy electrodes in theinter-detection-electrode region.

An electronic unit according to an embodiment of the disclosure includesthe display device with a touch detection function, and corresponds to atelevision device, a digital camera, a personal computer, a videocamera, or a portable terminal device such as a mobile phone.

In the first display device with a touch detection function, the touchdetection device, and the electronic unit according to the embodimentsof the disclosure, the arrangement area ratio of the touch detectionelectrode and the arrangement area ratio of the dummy electrodes in theinter-detection-electrode region are almost equal to each other by theaperture portions provided in the touch detection electrode. Therefore,when light enters from outside, reflectance is almost the same betweenthe touch detection electrode and the inter-detection-electrode region.

In the second display device with a touch detection function accordingto the embodiment of the disclosure, by the aperture portions providedin the touch detection electrode, the total length of all sides of theaperture portions per unit area is almost equal to the total length ofthe all sides of the dummy electrode per unit area. Therefore, whenlight enters from outside, reflectance is almost the same between thetouch detection electrode and the inter-detection-electrode region.

In the first display device with a touch detection function according tothe embodiment of the disclosure, for example, the aperture portions aredesirably provided so that the total length of all sides of the apertureportions per unit area is almost equal to the total length of all sidesof the dummy electrode per unit area.

For example, the touch detection electrode is desirably configured of aplurality of detection electrode unit cells each including the apertureportions, and the inter-detection-electrode region is desirablyconfigured of a plurality of dummy electrode unit cells each includingthe dummy electrode. For example, the size of each of the detectionelectrode unit cell and the dummy electrode unit cell is desirably equalto or smaller than 500 μm square. For example, the size of the detectionelectrode unit cell may correspond to the size of the dummy electrodeunit cell. For example, the detection electrode unit cell and the dummyelectrode unit cell are arranged in positions corresponding to theindividual display elements.

The display element may configure a display pixel including at least ared display element, a green display element, and a blue displayelement, and the size of the detection electrode unit cell maycorrespond to the size of the display pixel or an integral multiple ofthe size of the display pixel. Moreover, for example, the size of thedummy electrode unit cell may correspond to the size of the displaypixel or an integral multiple of the size of the display pixel.

The aperture portions may be arranged, for example, at least inpositions corresponding to a display element for color light with lowesttransmittance with respect to the electrode portion, out of the reddisplay element, the green display element, and the blue displayelement. In this case, for example, the aperture portions may bearranged in a position corresponding to the blue display element. Inaddition, the dummy electrodes may be arranged so that, out of the gapsbetween the adjacent dummy electrodes, the position of a gap extendingin a direction intersecting an arrangement direction of the red displayelement, the green display element, and the blue display elementcorresponds to the position of the blue display element.

For example, a selection line may be further provided for selecting adisplay element performing display operation, and the aperture portionsmay be arranged in a position corresponding to the selection line.

For example, the touch detection electrode may be formed directly on aglass substrate for supporting. Moreover, for example, the touchdetection electrode is formed on the glass substrate for supportingthrough a light transmitting layer, or is formed between the glasssubstrate and the light transmitting layer, and the refractive index ofthe light transmitting layer may have a value between a refractive indexof the glass substrate and a refractive index of the touch detectionelectrode.

Furthermore, the dummy electrodes may be in an electrical floatingstate.

For example, a plurality of drive electrodes may be arranged in parallelto extend in a direction intersecting the plurality of touch detectionelectrodes, and an electrostatic capacitance may be formed in eachintersection between the plurality of touch detection electrodes and theplurality of drive electrodes.

For example, the display element may be configured to include a liquidcrystal layer and pixel electrodes arranged to face the drive electrodeswith the liquid crystal layer in between, or may be configured toinclude a liquid crystal layer and pixel electrodes formed between theliquid crystal layer and the drive electrodes. In this case, the displayelement may be configured, for example, to be sandwiched between twopolarizing plates which are configured of a circularly polarizing plateor an elliptical polarizing plate.

In the first display device with a touch detection function, the touchdetection device, and the electronic unit according to the embodimentsof the disclosure, the aperture portions are provided in the touchdetection electrode, and the arrangement area ratio of the touchdetection electrode is almost equal to the arrangement area ratio of thedummy electrodes in the inter-detection-electrode region. Therefore, thereflectance is almost the same between the touch detection electrode andthe dummy electrode so that degradation of visibility of the displayscreen due to the touch detection electrodes is suppressed even in acase where light enters from outside.

Moreover, in the second display device with a touch detection functionaccording to the embodiment of the disclosure, the aperture portions areprovided in the touch detection electrode, and the total length of allsides of the aperture portions per unit area is almost equal to thetotal length of the all sides of the dummy electrode per unit area.Therefore, the reflectance is almost the same between the touchdetection electrode and the dummy electrode so that degradation ofvisibility of the display screen due to the touch detection electrode issuppressed even in a case where light enters from outside.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary, and are intended toprovide further explanation of the technology as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the disclosure, and are incorporated in and constitutea part of this specification. The drawings illustrate embodiments and,together with the specification, serve to explain the principles of thetechnology.

FIG. 1 is a diagram for explaining a basic principle of a touchdetection method in a display device with a touch detection functionaccording to embodiments of the disclosure, and a diagram illustrating astate where a finger is not in contact with or not in proximity to thedisplay device.

FIG. 2 is a diagram for explaining the basic principle of the touchdetection method in the display device with a touch detection functionaccording to the embodiments, and a diagram illustrating a state where afinger is in contact with or in proximity to the display device.

FIG. 3 is a diagram for explaining the basic principle of the touchdetection method in the display device with a touch detection functionaccording to the embodiments, and a diagram illustrating an example of awaveform of a drive signal and a touch detection signal.

FIG. 4 is a block diagram illustrating a configuration example of adisplay device with a touch detection function according to theembodiments.

FIG. 5 is a sectional view illustrating a schematic cross-sectionalconfiguration of a display section with a touch detection functionaccording to the embodiments.

FIGS. 6A and 6B are a circuit diagram and a plane view, respectively,both illustrating a pixel arrangement of the display section with atouch detection function according to the embodiments.

FIG. 7 is a perspective view illustrating a configuration example ofdrive electrodes and touch detection electrodes of the display sectionwith a touch detection function according to the embodiments.

FIG. 8 is a plane view illustrating a configuration example of a touchdetection electrode and dummy electrodes according to a firstembodiment.

FIGS. 9A and 9B are plane views for explaining an electrode area ratioand a ratio of electrode edge length.

FIGS. 10A and 10B are schematic views for explaining a measurement ofreflectance.

FIGS. 11A and 11B are characteristic diagrams illustrating an example ofdependency of the electrode area ratio and dependency of the ratio ofelectrode edge length of reflectance ratio.

FIGS. 12A and 12B are diagrams illustrating alignment marks according tothe embodiment.

FIG. 13 is a plane view illustrating a configuration example of a touchdetection electrode and dummy electrodes according to a modification ofthe first embodiment.

FIG. 14 is a plane view illustrating a configuration example of a touchdetection electrode and dummy electrodes according to a secondembodiment.

FIGS. 15A and 15B are plane views for explaining a vertical electrodeedge length according to the second embodiment.

FIG. 16 is a plane view illustrating a configuration example of a touchdetection electrode and dummy electrodes according to a modification ofthe second embodiment.

FIGS. 17A and 17B are plane views for explaining a lateral electrodeedge length according to the modification of the second embodiment.

FIG. 18 is a plane view illustrating a configuration example of a touchdetection electrode and dummy electrodes according to a thirdembodiment.

FIG. 19 is a table illustrating example according to the embodiment.

FIG. 20 is a perspective view illustrating an appearance configurationof an application example 1 of the display device with a touch detectionfunction applied with the embodiment.

FIGS. 21A and 21B are perspective views illustrating an appearanceconfiguration of an application example 2.

FIG. 22 is a perspective view illustrating an appearance configurationof an application example 3.

FIG. 23 is a perspective view illustrating an appearance configurationof an application example 4.

FIGS. 24A to 24G are front views, side views, a top view, and a bottomview illustrating an appearance configuration of an application example5

FIG. 25 is a sectional view illustrating a schematic cross-sectionalconfiguration of a display section with a touch detection functionaccording to a modification of the embodiment.

FIG. 26 is a sectional view illustrating a schematic cross-sectionalconfiguration of a display section with a touch detection functionaccording to another modification of the embodiment.

DETAILED DESCRIPTION

Hereinafter, preferred embodiments of the disclosure will be describedin detail with reference to drawings. The description will be given inthe following order.

-   1. Basic principle of electrostatic capacitance type touch detection-   2. First embodiment-   3. Second embodiment-   4. Third embodiment-   5. Example-   6. Application examples

1. BASIC PRINCIPLE OF ELECTROSTATIC CAPACITANCE TYPE TOUCH DETECTION

First, a basic principle of touch detection in a display device with atouch detection function according to embodiments of the disclosure willbe described with reference to FIG. 1 to FIG. 3. The touch detectionmethod is implemented as an electrostatic capacitance type touch sensor,and a capacitance element is configured with use of a pair of electrodes(a drive electrode E1 and a touch detection electrode E2) facing to eachother with a dielectric body D in between as illustrated in (A) ofFIG. 1. The configuration is represented as an equivalent circuitillustrated in (B) of FIG. 1. A capacitance element C1 is configured ofthe drive electrode E1, the touch detection electrode E2, and thedielectric body D. One end of the capacitance element C1 is connected toan alternating signal source (a drive signal source) S, and the otherend P is grounded through a resistor R and is connected to a voltagedetector (a touch detection circuit) DET. When an alternatingrectangular wave Sg ((B) of FIG. 3) with a predetermined frequency (forexample, several kHz to several tens kHz) is applied to the driveelectrode E1 (one end of the capacitance element C1) from thealternating signal source S, an output waveform (a touch detectionsignal Vdet) illustrated in (A) of FIG. 3 appears in the touch detectionelectrode E2 (the other end P of the capacitance element C1). Note thatthe alternating rectangular wave Sg corresponds to a drive signal Vcomdescribed later.

In a state where a finger is not in contact with (or not in proximityto) the display device, as illustrated in FIG. 1, a current I0 accordingto the capacitance value of the capacitance element C1 flows in responseto charge and discharge with respect to the capacitance element C1. Theother end P of the capacitance element C1 at this time has a potentialwaveform like a waveform V0 in (A) of FIG. 3, and the waveform isdetected by the voltage detector DET.

On the other hand, in a state where a finger is in contact with (or inproximity to) the display device, as illustrated in FIG. 2, acapacitance element C2 formed by the finger is added in series with thecapacitance element C1. In this state, currents I1 and I2 flow inresponse to charge and discharge with respect to the capacitanceelements C1 and C2, respectively. The other end P of the capacitanceelement C1 at this time has a potential waveform like a waveform V1 in(A) of FIG. 3, and the waveform is detected by the voltage detector DET.At this time, the potential of the point P is a partial potentialdetermined by values of the currents I1 and I2 flowing through thecapacitance elements C1 and C2. Therefore, the waveform V1 is a smallervalue than that of the waveform V0 in a non-contact state. The voltagedetector DET compares the detected voltage with a predeterminedthreshold voltage Vth to determine the non-contact state when thedetected voltage is equal to or larger than the threshold voltage, andto determine a contact state when the detected voltage is smaller thanthe threshold voltage. In such a way, touch detection is achievable.

2. FIRST EMBODIMENT CONFIGURATION EXAMPLE General Configuration Example

FIG. 4 illustrates a configuration example of a display device with atouch detection function 1 according to a first embodiment of thedisclosure. Incidentally, a touch detection device according to theembodiment of the disclosure is implemented by the first embodiment, sothe description thereof will be given together. The display device witha touch detection function uses a liquid crystal display element as adisplay element, and is of a so-called in-cell type in which a liquidcrystal display section configured by the liquid crystal displayelement, and an electrostatic capacitance type touch detection sectionare integrated.

The display device with a touch detection function 1 includes a controlsection 11, a gate driver 12, a source driver 13, a drive electrodedriver 14, a display section with a touch detection function 10, and atouch detection circuit 40.

The control section 11 is a circuit supplying a control signal to thegate driver 12, the source driver 13, the drive electrode driver 14, andthe touch detection circuit 40 based on a picture signal Vdisp suppliedfrom outside, and controlling these parts to operate in synchronizationwith one another.

The gate driver 12 has a function to sequentially select one horizontalline which is a target of display drive of the display section with atouch detection function 10, based on the control signal supplied fromthe control section 11. Specifically, as described later, the gatedriver 12 applies a scan signal Vscan to a gate of a TFT element Tr of apixel Pix through a scan signal line GCL to sequentially select, as atarget of display drive, one row (one horizontal line) in the pixels Pixformed in a matrix in a liquid crystal display section 20 of the displaysection with a touch detection function 10.

The source driver 13 is a circuit supplying a pixel signal Vpix to eachpixel Pix (described later) in the display section with a touchdetection function 10 based on the control signal supplied from thecontrol section 11. Specifically, the source driver 13 supplies thepixel signal Vpix to each pixel Pix configuring one horizontal linesequentially selected by the gate driver 12 through a pixel signal lineSGL as described later. Then, in the pixels Pix, display for thehorizontal line is performed in response to the supplied pixel signalVpix.

The drive electrode driver 14 is a circuit supplying a drive signal Vcomto drive electrodes COML (described later) of the display section with atouch detection function 10 based on the control signal supplied fromthe control section 11. Specifically, the drive electrode driver 14sequentially applies the drive signal Vcom to the drive electrodes COMLin a time-divisional manner. Then, a touch detection section 30 outputsa touch detection signal Vdet based on the drive signal Vcom from aplurality of touch detection electrodes TDL (described later), andsupplies the signal to the touch detection circuit 40.

The display section with a touch detection function 10 is a displaysection incorporating a touch detection function. The display sectionwith a touch detection function 10 includes the liquid crystal displaysection 20 and the touch detection section 30. As described later, theliquid crystal display section 20 is a section performing sequentialscan on one horizontal line basis to perform display according to thescan signal Vscan supplied from the gate driver 12. The touch detectionsection 30 operates based on the above-described basic principle of theelectrostatic capacitance type touch detection, and outputs the touchdetection signal Vdet. As described later, the touch detection section30 performs sequential scan according to the drive signal Vcom suppliedfrom the drive electrode driver 14 to perform touch detection.

The touch detection circuit 40 is a circuit detecting the presence oftouch events with respect to the touch detection section 30 based on thecontrol signal supplied from the control section 11 and the touchdetection signal Vdet supplied from the touch detection section 30 ofthe display section with a touch detection function 10, and when thetouch event is detected, the touch detection circuit 40 determines thecoordinate and the like in a touch detection region to output thecoordinate and the like as an output signal Out.

(Display Section with a Touch Detection Function 10)

Next, the configuration example of the display section with a touchdetection function 10 will be described in detail.

FIG. 5 illustrates an example of a cross-sectional configuration of arelevant part of the display section with a touch detection function 10.The display section with a touch detection function 10 has a pixelsubstrate 2, a facing substrate 3 disposed to face the pixel substrate2, and a liquid crystal layer 6 inserted between the pixel substrate 2and the facing substrate 3.

The pixel substrate 2 includes a TFT substrate 21 as a circuit substrateand a plurality of pixel electrodes 22 arranged in a matrix on the TFTsubstrate 21. In the TFT substrate 21, although not illustrated, thinfilm transistors (TFTs) for each pixels, and wires such as the pixelsignal line SGL for supplying the pixel signal Vpix to each of the pixelelectrodes 22, and the scan signal line GCL for driving each TFT areformed.

The facing substrate 3 includes a glass substrate 31, a color filter 32formed on a surface of the glass substrate 31, and a plurality of driveelectrodes COML formed on the color filter 32. The color filter 32 isconfigured by cyclically arranging three color filter layers of red (R),green (G), and blue (B), and a set of three colors of R, G, and Bcorresponds to each display pixel. The drive electrodes COML function ascommon drive electrodes for the liquid crystal display section 20, andfunction as drive electrodes for the touch detection section 30. Notethat in this example, although the drive electrodes are shared fordisplay and for touch detection, the drive electrodes for display andfor touch detection may be separately provided. The drive electrodesCOML are connected to the TFT substrate 21 by a contact conductingcylinder (not illustrated), and the drive signal Vcom with thealternating rectangular waveform is applied from the TFT substrate 21 tothe drive electrodes COML through the contact conducting cylinder. Alight transmitting layer 33 is formed on the other surface of the glasssubstrate 31, and touch detection electrodes TDL as detection electrodesof the touch detection section 30 are formed on the light transmittinglayer 33. Each of the touch detection electrodes TDL is composed of, forexample, ITO (indium tin oxide), IZO, and SnO, and is an electrode withtranslucency. Each of the touch detection electrodes TDL has a pluralityof aperture portions as described later. The light transmitting layer 33is composed of an insulating material such as SiN and SiC, and therefractive index thereof is a value (for example, approximately 1.75 inthe case of SiN, and approximately 1.6 in the case of SiC) between therefractive index (for example, approximately 1.5) of the glass substrate31 and the refractive index (for example, approximately 1.8) of thetouch detection electrodes TDL in the vicinity of the wavelength 550 nmwith high visibility. The light transmitting layer 33 is provided as anindex matching layer for reducing reflection between the glass substrate31 and the touch detection electrodes TDL. Moreover, on the touchdetection electrode TDL, a polarizing plate 35 is disposed.

The liquid crystal layer 6 modulates light passing therethroughaccording to a state of electric field, and liquid crystal of variousmodes such as TN (twisted nematic), VA (vertical alignment), and ECB(electrically controlled birefringence) is used.

Incidentally, an alignment film is disposed between the liquid crystallayer 6 and the pixel substrate 2, and between the liquid crystal layer6 and the facing substrate 3, which is not illustrated in the figure. Inaddition, an incident-side polarizing plate is disposed on a bottomsurface side of the pixel substrate 2, which is not illustrated in thefigure. As the polarizing plate 35 and the incident-side polarizingplate (not illustrated), a circularly polarizing plate or an ellipticalpolarizing plate is used.

FIGS. 6A and 6B illustrate a configuration example of a pixelconfiguration in the liquid crystal display section 20, where FIG. 6A isa circuit diagram thereof, and FIG. 6B is a plane view thereof. Theliquid crystal display section 20 has the plurality of pixels Pixarranged in a matrix. Each pixel Pix is configured of three sub-pixelsSPix. The three sub-pixels SPix are arranged to correspond to threecolors (RGB) of the color filter 32 illustrated in FIG. 5, respectively.Each of the sub-pixels SPix has a TFT element Tr and a liquid crystalelement LC. The TFT element Tr is configured of a thin film transistor,and in this example, the TFT element Tr is configured of an n-channelMOS (metal oxide semiconductor) TFT. A source of the TFT element Tr isconnected to the pixel signal line SGL, a gate thereof is connected tothe scan signal line GCL, and a drain thereof is connected to one end ofthe liquid crystal element LC. One end of the liquid crystal element LCis connected to the drain of the TFT element Tr, and the other endthereof is connected to the drive electrode COML.

Each of the sub-pixels SPix is connected, with respect to each other, bythe scan signal line GCL, to the other sub-pixels SPix which are in thesame row of the liquid crystal display section 20. The scan signal lineGCL is connected to the gate driver 12, and the scan signal Vscan issupplied from the gate driver 12. In addition, each of the sub-pixelsSPix is connected, with respect to each other, by the pixel signal lineSGL, to the other sub-pixels SPix which are in the same column of theliquid crystal display section 20. The pixel signal line SGL isconnected to the source driver 13, and the pixel signal Vpix is suppliedfrom the source driver 13.

The pixel signal line SGL and the scan signal line GCL are arranged in aboundary between the adjacent sub-pixels SPix as illustrated in FIG. 6B.Specifically, the pixel signal line SGL is arranged in a boundarybetween the laterally adjacent sub-pixels SPix, and the scan signal lineGCL is arranged in a boundary between the vertically adjacent sub-pixelsSPix. The pixel signal line SGL and the scan signal line GCL areconfigured of a single-layer film or a multilayer film of aluminum,aluminum alloy, molybdenum, and titanium, for example. Therefore, lightis not transmitted in a portion corresponding to the pixel signal lineSGL and/or the scan signal line GCL.

In addition, each of the sub-pixels Spix is connected, with respect toeach other, to the other sub-pixels SPix which are in the same row ofthe liquid crystal display section 20 by the drive electrodes COML. Thedrive electrodes COML are connected to the drive electrode driver 14,and the drive signal Vcom is supplied from the drive electrode driver14.

With this configuration, in the liquid crystal display section 20, thegate driver 12 drives the scan signal line GCL to performline-sequential scan in a time-divisional manner so that one horizontalline is sequentially selected. Then, the source driver 13 supplies thepixel signal Vpix to the pixels Pix in the selected horizontal line toperform display on one horizontal line basis.

FIG. 7 is a perspective view illustrating a configuration example of thetouch detection section 30. The touch detection section 30 is configuredof the drive electrodes COML and the touch detection electrodes TDLarranged in the facing substrate 3. Each of the drive electrodes COML isconfigured of a stripe-shaped electrode pattern extending in a lateraldirection of the figure. When a touch detection operation is performed,the drive signal Vcom is sequentially supplied to each of the electrodepatterns by the drive electrode driver 14, and sequential scan drive isperformed in a time-divisional manner. Each of the touch detectionelectrodes TDL is configured of an electrode pattern extending in adirection intersecting with an extending direction of the electrodepattern of each of the drive electrode COML. As described later, dummyelectrodes 37 (not illustrated) are arranged between the touch detectionelectrodes TDL (an inter-detection-electrode region). Each of the touchdetection electrodes TDL includes an electrode pattern including theplurality of aperture portions which is provided for adjusting thereflectance of the touch detection electrodes TDL and the reflectance ofthe dummy electrodes 37 to be equal to each other. The electrode patternof each of the touch detection electrodes TDL is connected to the touchdetection circuit 40. The electrode patterns of the drive electrode COMLand the electrode patterns of the touch detection electrodes TDLintersecting with each other form an electrostatic capacitance at eachintersection.

With this configuration, in the touch detection section 30, the driveelectrode driver 14 applies the drive signal Vcom to the driveelectrodes COML to output the touch detection signal Vdet from the touchdetection electrodes TDL, and therefore touch detection is performed.The drive electrodes COML correspond to the drive electrode E1 in thebasic principle of touch detection illustrated in FIG. 1 to FIG. 3, thetouch detection electrodes TDL correspond to the touch detectionelectrode E2, and the touch detection section 30 detects touch events inaccordance with the basic principle. As illustrated in FIG. 7, theelectrode patterns intersecting with each other configure anelectrostatic capacitance type touch sensor in a matrix. Therefore, scanis performed over the entire touch detection surface of the touchdetection section 30 so that a contact position or a proximal positionof the external proximity object is detectable.

FIG. 8 illustrates a configuration example of the touch detectionelectrode TDL. The touch detection electrode TDL has a plurality ofaperture portions 36 (aperture portions 36A and 36B) in a display regionSd arranged with the pixels Pix. The aperture portions 36 are formed tocorrespond to the pixels Pix. Specifically, the aperture portion 36A isformed in a portion corresponding to the sub-pixel SPix of blue (B). Theaperture portion 36B is formed in a position corresponding to a boundarybetween the vertically adjacent pixels Pix in the figure. In otherwords, the aperture portion 36B is arranged in a position correspondingto the scan signal line GCL formed in the pixel substrate 2, namely, ina position where light is not transmitted. In this way, the apertureportions 36 are formed with a cycle of the pixel Pix. In other words,the touch detection electrode TDL is formed with the pixel Pix as a unitcell UC. The unit cell UC desirably has a size invisible by human eyes,for example, is desirably equal to or smaller than 500 μm. The touchdetection electrode TDL is formed to extend to a frame region Sf outsideof the display region Sd, and is connected to the touch detectioncircuit 40.

In a region between the adjacent touch detection electrodes TDL (aninter-detection-electrode region Rd), the plurality of dummy electrodes37 are provided. Each of the dummy electrodes 37 is composed of ITOsimilar to the touch detection electrode TDL. The dummy electrodes 37are also provided to correspond to the pixels Pix. Specifically, in FIG.8, the dummy electrodes 37 are arranged so that a gap between thelaterally adjacent dummy electrodes 37 in the figure corresponds to thesub-pixel SPix of blue (B) in the pixel Pix. Moreover, the dummyelectrodes 37 are arranged so that a gap between the vertically adjacentdummy electrodes 37 in the figure corresponds to a boundary of thepixels Pix. In this way, the dummy electrodes 37 are also formed with acycle of the pixel Pix. Like the unit cell UC, the dummy electrode 37desirably has a size invisible by human eyes, and for example, isdesirably equal to or smaller than 500 μm. Each of the dummy electrodes37 is not electrically connected with other parts, and is in a floatingstate.

The reason why the aperture portions 36A in the touch detectionelectrode TDL, and the gap between the laterally adjacent dummyelectrodes 37 are arranged to correspond to the sub-pixel SPix of blue(B) is that the light transmittance of the electrode in blue (B) is thelowest between red (R), green (G), and blue (B). In other words, byarranging the sub-pixel SPix of blue (B) in the aperture portion 36A orthe gap between the dummy electrodes 37, light intensity of blue islowered in these electrodes to prevent the chromaticity of white fromchanging to yellow.

FIG. 9A illustrates a configuration example of the unit cell UC of thetouch detection electrode TDL, and FIG. 9B illustrates a configurationexample of the dummy electrode 37. In the display device with a touchdetection function 1, an area (hatched portion) of a portion arrangedwith the electrode in the unit cell UC of the touch detection electrodeTDL illustrated in FIG. 9A is almost equal to an area (hatched portion)of the dummy electrode 37 illustrated in FIG. 9B. In other words, anarrangement area ratio of the touch detection electrode TDL is almostequal to an arrangement area ratio of the dummy electrodes in theinter-detection-electrode region Rd.

In this case, the sub-pixel SPix corresponds to a specific example of “adisplay element” of the disclosure. The aperture portions 36A and 36Bcorrespond to a specific example of “an aperture portion” of thedisclosure. The unit cell UC corresponds to a specific example of “adetection electrode unit cell” of the disclosure. The pixel Pixcorresponds to a specific example of “a display pixel” of thedisclosure. The scan signal line GCL corresponds to a specific exampleof “a selection line” of the disclosure.

[Functions and Effects]

Subsequently, functions and effects of the display device with a touchdetection function 1 according to the embodiment will be described.

(General Operation Outline)

The control section 11 supplies the control signal to the gate driver12, the source driver 13, the drive electrode driver 14, and the touchdetection circuit 40 based on the picture signal Vdisp supplied fromoutside, and controls these parts to operate in synchronization with oneanother. The gate driver 12 supplies the scan signal Vscan to the liquidcrystal display section 20 to sequentially select one horizontal line tobe driven for display. The source driver 13 supplies the pixel signalVpix to each pixel Pix configuring one horizontal line selected by thegate driver 12. The drive electrode driver 14 sequentially applies thedrive signal Vcom to the drive electrodes COML. The display section witha touch detection function 10 performs display operation, and performstouch detection operation based on the drive signal Vcom to output thetouch detection signal Vdet from the touch detection electrodes TDL. Thetouch detection circuit 40 determines presence of touch events withrespect to the touch detection section 30 and the touch coordinate, andoutputs the result as the output signal Out.

In the display device with a touch detection function 1, the touchdetection electrodes TDL and the dummy electrodes are formed so that theelectrode area per unit cell UC (pixel Pix) in the touch detectionelectrode TDL is almost equal to the electrode area per unit cell UC inthe inter-detection-electrode region Rd. Therefore, in a case wherelight enters from outside, the reflectance in the touch detectionelectrode TDL has a value close to the reflectance in theinter-detection-electrode region Rd, the touch detection electrode TDLis hardly viewed, and therefore the visibility of the display screen isimproved. Hereinafter, the detail thereof will be described.

(Reflectance Ratio)

FIGS. 10A and 10B schematically illustrate measurements of thereflectance, where FIG. 10A illustrates a measurement in the touchdetection electrode TDL, and FIG. 10B illustrates a measurement in theinter-detection-electrode region Rd. In the measurements, light isirradiated to each of the touch detection electrode TDL and theinter-detection-electrode region Rd, and each of the reflectance in arange (measurement area M) of a circle with a diameter of 600 μm at thattime is determined. Then, a reflectance ratio Rref is obtained bydividing the reflectance in the inter-detection-electrode region Rd bythe reflectance in the touch detection electrode TDL. As is obvious fromthe definition, it means that the closer the reflectance ratio Rref isto 100%, the closer the reflectance in the inter-detection-electroderegion Rd is to the reflectance in the touch detection electrode TDL. Inother words, as the reflectance ratio Rref is close to 100%, the touchdetection electrode TDL is hardly viewed even when light enters fromoutside.

It is considered that light reflection is contributed by not only a topsurface (for example, the hatched portions in FIGS. 9A and 9B) of theelectrode but also a side surface (for example, edge portions E in FIGS.9A and 9B) of the electrode. Therefore, a plurality of samples in whichthe area of the hatched portion (electrode area S) and a total length ofthe edge portion E (electrode edge length LE) are different from oneanother was made, and the reflectance ratio Rref of each of the sampleswas measured.

FIGS. 11A and 11B illustrate measurement results of the reflectanceratio Rref, where FIG. 11A illustrates dependency of an electrode arearatio RS, and FIG. 11B illustrates dependency of a ratio of electrodeedge length RLE. In this case, the electrode area ratio RS is obtainedby dividing the electrode area per unit cell UC (pixel Pix) in theinter-detection-electrode region Rd by the electrode area per unit cellUC in the touch detection electrode TDL. In addition, the ratio ofelectrode edge length RLE is obtained by dividing the electrode edgelength per unit cell UC (pixel Pix) in the inter-detection-electroderegion Rd by the electrode edge length per unit cell UC in the touchdetection electrode TDL.

As illustrated in FIG. 11A, the reflectance ratio Rref has a strongcorrelation with the electrode area ratio RS, and the larger theelectrode area ratio RS is, the larger the reflectance ratio Rref is. Inaddition, as illustrated in FIG. 11B, the reflectance ratio Rref has aweak correlation with the ratio of electrode edge length RLE, and thelonger the ratio of electrode edge length RLE is, the larger thereflectance ratio Rref is.

In the display device with a touch detection function 1, it is focusedon the strong correlation between the reflectance ratio Rref and theelectrode area ratio RS, and the touch detection electrodes TDL and thedummy electrodes 37 are formed so that the electrode area per unit cellUC (pixel Pix) in the touch detection electrode TDL is almost equal tothe electrode area per unit cell UC in the inter-detection-electroderegion Rd. This is achievable by providing the aperture portions 36 inthe touch detection electrode TDL. Specifically, for example, theaperture width Wa of the aperture 36A and the aperture width Wb of theaperture 36B are adjusted so as to be wider than the distance betweenthe adjacent dummy electrodes 37, and therefore the electrode area perunit cell UC (pixel Pix) in the touch detection electrode TDL is almostequal to the electrode area per unit cell UC in theinter-detection-electrode region Rd. Consequently, the reflectance inthe touch detection electrode TDL may be set to a value close to thereflectance in the inter-detection-electrode region Rd. Therefore, evenwhen light enters from outside, the touch detection electrode TDL ishardly viewed, and the visibility of the display screen may be improved.

In addition, as illustrated in FIG. 5, the polarizing plate 35 is formedon the display surface of the display device with a touch detectionfunction 1. Accordingly, reflection light itself from the touchdetection electrodes TDL or the dummy electrode 37 may be reduced, andtherefore the touch detection electrodes TDL may be hardly viewed.

Although example will be described in detail later with reference toFIG. 19, the electrode area ratio RS is allowed to be close to 100%, andthus the reflectance ratio Rref may be closed to 100%. Therefore, it isconfirmed that the visibility of the display screen is improved evenwhen light enters from outside.

(Alignment Marks)

As illustrated in FIG. 8, in the display device with a touch detectionfunction 1, the aperture portions 36 and the dummy electrodes 37 arearranged to correspond to the pixels Pix. This means that when the touchdetection electrodes TDL and the dummy electrodes 37 are formed on thefacing substrate 3, alignment with the pixels Pix is necessary.Hereinafter, alignment marks used for the alignment will be described indetail.

In the process of manufacturing the display device with a touchdetection function 1, for example, a large pixel substrate 102manufactured in a step of manufacturing the pixel substrate and a largefacing substrate 103 manufactured in a step of manufacturing the facingsubstrate are overlaid with each other, the overlaid glass is reduced inthickness by grinding or etching as necessary, and then the touchdetection electrode TDL and the dummy electrodes 37 are formed on thefacing substrate 103. After these electrodes and the like are formed,the overlaid large substrates are cut, the various components areattached to each of the cut substrates, and the display device with atouch detection function 1 is assembled.

In the example of the manufacturing process, the touch detectionelectrodes TDL and the dummy electrodes 37 are formed after the largepixel substrate 102 and the large facing substrate 103 are overlaid.Therefore the alignment marks used for the formation of the electrodesmay be alignment marks used in the step of manufacturing the pixelsubstrate or may be alignment marks used in the step of manufacturingthe facing substrate.

FIG. 12A illustrates an example of the alignment marks of the largepixel substrate 102, and FIG. 12B illustrates an example of thealignment marks of the large facing substrate 103. The alignment marksof the large pixel substrate 102 illustrated in FIG. 12A are used forforming the TFT element Tr, the pixel electrode 22, the pixel signalline SGL, the scan signal line GCL, and the like on the TFT substrate 21or for examining them in the step of manufacturing the pixel substrate.The alignment marks of the large facing substrate 103 illustrated inFIG. 12B are used for forming the color filter 32, the drive electrodesCOML, and the like on the glass substrate 31, or for examining them inthe step of manufacturing the facing substrate.

To use the alignment marks at the time of forming the touch detectionelectrodes TDL and the dummy electrodes 37, the alignment marks need tobe detectable from outside at the time of overlaying the large pixelsubstrate 102 and the large facing substrate 103. Specifically, forexample, in a case where an alignment mark A1 of the large pixelsubstrate 102 illustrated in FIG. 12A is used for forming the touchdetection electrodes TDL and the like, at the position on the largefacing substrate 103 corresponding to the position of the alignment markA1, it is necessary that no pattern is provided. In addition, in a casewhere an alignment mark A2 of the large facing substrate 103 illustratedin FIG. 12B is used for forming the touch detection electrodes TDL andthe like, at the position on the large pixel substrate 102 correspondingto the position of the alignment mark A2, it is necessary that nopattern is provided. In this way, even when the large pixel substrate102 and the large facing substrate 103 are overlaid, the alignment marks(for example, the alignment marks A1 and A2) used for forming the touchdetection electrodes TDL are detected, and therefore misrecognition ofthe device and error in reading may be prevented.

Although in the above description, the touch detection electrodes TDLand the dummy electrodes 37 are formed after the large pixel substrate102 and the large facing substrate 103 are overlaid, this is notlimitative. Alternatively, for example, after the touch detectionelectrodes TDL and the dummy electrodes 37 are formed on the largefacing substrate in the step of manufacturing the facing substrate, thelarge pixel substrate 102 and the large facing substrate 103 may beoverlaid. In this case, for example, in the step of manufacturing thefacing substrate, the touch detection electrodes TDL and the dummyelectrodes 37 may be formed after the facing substrate pattern of thecolor filter and the like is formed, or the facing substrate pattern maybe formed after the touch detection electrodes TDL and the dummyelectrodes 37 are formed. In this case, the touch detection electrodesTDL and the like are formed with use of the alignment marks of the largefacing substrate in the step of manufacturing the facing substrate.

(Effects)

In the embodiment as described above, the aperture portions are providedin the touch detection electrodes. Therefore, the electrode area perunit cell UC (pixel Pix) in the touch detection electrode may be almostequal to the electrode area per unit cell UC in theinter-detection-electrode region. In addition, the reflectance ofrespective regions are almost equal to each other, and thereforevisibility of the display screen may be improved when light enters fromoutside.

In the embodiment, some of the aperture portions of the touch detectionelectrode are arranged at the positions corresponding to the scan signalline so that influence of change in luminance caused by the apertureportions may be reduced.

In the embodiment, some of the aperture portions of the touch detectionelectrode are provided in the sub-pixel region of blue so that the colorshift of white caused by the reduced light intensity of blue in thetouch detection electrode may be suppressed.

In the embodiment, the alignment marks used for manufacturing the pixelsubstrate and the facing substrate are commonly used to form the touchdetection electrodes and the dummy electrodes so that the position ofthe pixels and the position of the touch detection electrodes areadjusted with high precision. Therefore, the gap between the position ofthe displayed object and the touch detection position when the displayedobject on the display device is touched may be reduced, and the highprecision of the position detection is achievable. In addition, it isunnecessary to provide dedicated alignment marks for forming the touchdetection electrodes and the dummy electrodes, thereby making thepattern simple.

[Modification 1-1]

Although in the above-described embodiment, the dummy electrodes havebeen formed with the cycle of the pixel Pix, this is not limitative.Alternatively, for example, the dummy electrodes may be formed with acycle of a plurality of pixels Pix. Exemplified below is a case whereeach of the dummy electrodes is formed with a cycle of four pixels Pix.

FIG. 13 illustrates a configuration example of a dummy electrode 37B ofa display device with a touch detection function 1B according to themodification. The dummy electrode 37B has a shape in which the adjacentfour dummy electrodes 37 in FIG. 8 are connected with one another. Thedummy electrode 37B has aperture portions 38 and 39 at the positionscorresponding to the gap between the four dummy electrodes 37 in FIG. 8.The dummy electrode 37B is desirably has a size invisible by human eyes,and is, for example, desirably equal to or smaller than 500 μm, similarto the dummy electrode 37 or the like. Also in this case, for example,the aperture width Wa of the aperture portion 36A and the aperture widthWb of the aperture portion 36B are adjusted so that an arrangement arearatio of the touch detection electrode TDL is almost equal to anarrangement area ratio of the dummy electrodes in theinter-detection-electrodes region Rd. Therefore, when light enters fromoutside, visibility of the display screen may be improved.

[Modification 1-2]

Although in the above-described embodiment, the unit cell UC has beenintended to correspond to the size of the pixel Pix, this is notlimitative. For example, the unit cell UC may correspond to the size ofthe plurality of pixels Pix. Specifically, in FIG. 8, for example,either one of two aperture portions 36B vertically arranged in thefigure is removed so that the unit cell UC may correspond to the size ofthe two pixels Pix.

3. SECOND EMBODIMENT

Next, a display device with a touch detection function 5 according to asecond embodiment of the disclosure will be described. In the secondembodiment, aperture portions of the touch detection electrode areformed based on not only the electrode area but also the electrode edgelength. In other words, the display device with a touch detectionfunction 5 is configured by using a display section with a touchdetection function 50 including such aperture portions. Otherconfigurations are the same as that in the above-described firstembodiment (FIG. 4 and the like). Note that like numerals are used todesignate substantially like components of the display device with atouch detection function 1 according to the first embodiment, and thedescription thereof are appropriately omitted.

FIG. 14 illustrates a configuration example of a touch detectionelectrode TDL2 of the display device with a touch detection function 5.The touch detection electrode TDL2 has aperture portions 36C, 36D, and36E in the display region Sd arranged with the pixels Pix. The apertureportions 36C and 36D are formed in a portion corresponding to thesub-pixel SPix of blue (B), and the aperture portion 36E is arranged ina position corresponding to a boundary between vertically adjacentpixels Pix in the figure.

FIGS. 15A and 15B are plane views for explaining the electrode arearatio RS and the ratio of electrode edge length RLE in the displaydevice with a touch detection function 5, where FIG. 15A illustrates aunit cell UC of the touch detection electrode TDL2, and FIG. 15Billustrates the dummy electrode 37.

In the display device with a touch detection function 5, similar to thedisplay device with a touch detection function 1 according to theabove-described first embodiment and the like, the electrode area(hatched portion in FIG. 15A) per unit cell UC in the touch detectionelectrode TDL2 is almost equal to the electrode area (hatched area inFIG. 15B) of the dummy electrode 37. Specifically, for example, theaperture width Wa of each of the aperture portions 36C and 36D and theaperture width Wb of the aperture portion 36E are adjusted so that theelectrode area per unit cell UC in the touch detection electrode TDL2 isalmost equal to the electrode area of the dummy electrode 37. Note thatthe aperture width Wa and the aperture width Wb may be equal to eachother, or may be different from each other.

Moreover, in the display device with a touch detection function 5, inFIG. 15, the electrode edge length in the vertical direction in thetouch detection electrode TDL2 is almost equal to that in theinter-detection-electrode region Rd. Specifically, the total length offour vertical edge portions ET (the electrode edge length in thevertical direction) according to the left side of the electrode in FIG.15A is almost equal to the length of the vertical edge portion ETaccording to the left side of the dummy electrode 37 in FIG. 15B.

In the display device with a touch detection function 5, the touchdetection electrode TDL2 and the dummy electrode 37 are formed so thatthe electrode edge length in the vertical direction in the touchdetection electrode TDL 2 is almost equal to that in theinter-detection-electrode region Rd, besides the electrode area per unitcell UC (pixel Pix). Therefore, the reflectance in the touch detectionelectrode TDL2 may have a value close to the reflectance in theinter-detection-electrode region Rd.

Although example will be described in detail later with reference toFIG. 19, it is confirmed that the electrode area ratio RS and the ratioof electrode edge length RLE are close to 100% so that the reflectanceratio Rref is close to 100%. Therefore, when light enters from outside,visibility of the display screen may be improved.

In the embodiment as described above, in addition to the electrode area,the electrode edge length in the vertical direction in the touchdetection electrode has been almost equal to that in theinter-detection-electrode region. Therefore, by allowing the reflectancein each region to be almost equal to each other, even when light entersfrom outside, visibility of the display screen may be improved. Othereffects are the same as in the above-described first embodiment.

[Modification 2]

Although in the above-described embodiment, the aperture portions havebeen configured so that the electrode edge length in the verticaldirection is the same between the touch detection electrode and theinter-detection-electrode region, this is not limitative. Alternatively,for example, the aperture portions may be configured so that theelectrode edge length in the lateral direction is the same. The examplewill be described below.

FIG. 16 illustrates an example of a touch detection electrode TDL2B in adisplay device with a touch detection function 5B according to themodification. The touch detection electrode TDL2B has aperture portions36F and 36G. The aperture portion 36F is formed in a portioncorresponding to the sub-pixel SPix of blue (B), and the apertureportion 36G is formed in a position corresponding to a boundary betweenvertically adjacent pixels Pix in the figure. The aperture portion 36Fis shaped like a letter “I”, and therefore, the electrode edge lengththereof in the lateral direction may be adjusted.

FIGS. 17A and 17B are plane views for explaining the electrode arearatio RS and the ratio of electrode edge length RLE of the displaydevice with a touch detection function 5B, where FIG. 17A illustrates aunit cell UC of the touch detection electrode TDL2B, and FIG. 17Billustrates the dummy electrode 37. In the display device with a touchdetection function 5B, similar to the display device with a touchdetection function 5 in the embodiment, the electrode area (hatchedportion in FIG. 17A) per unit cell UC in the touch detection electrodeTDL2B is almost equal to the electrode area (hatched portion in FIG.17B) of the dummy electrode 37. Specifically, for example, the aperturewidth Wa of the aperture portion 36F and the aperture width Wb of theaperture portion 36G are adjusted so that the electrode areas thereofare almost equal to each other. In addition, in the display device witha touch detection function 5B, in FIG. 17, the electrode edge length inthe lateral direction is almost the same between the touch detectionelectrode TDL2B and the inter-detection-electrode region Rd.Specifically, the total length of four lateral edge portions EYaccording to the top side of the electrode in FIG. 17A is almost equalto the length of a lateral edge portion EY according to the top side ofthe dummy electrode 37 in FIG. 17B.

4. THIRD EMBODIMENT

Next, a display device with a touch detection function 7 according to athird embodiment of the disclosure will be described. In the thirdembodiment, the aperture portions of the touch detection electrode areconfigured such that both the electrode area and the electrode edgelength are almost the same between the touch detection electrode and theinter-detection-electrode region. In other words, the display devicewith a touch detection function 7 is configured by using a displaysection with a touch detection function 70 having such apertureportions. The other configurations are the same as in theabove-described first embodiment (FIG. 4 and the like). Note that likenumerals are used to designate substantially like components of thedisplay device with a touch detection function 1 according to the firstembodiment, and the description thereof are appropriately omitted.

FIG. 18 illustrates a configuration example of a touch detectionelectrode TDL3 of the display device with a touch detection function 7.The touch detection electrode TDL3 has aperture portions 36H and 36I inthe display region Sd arranged with the pixels Pix. The aperture portion36H is formed in a portion corresponding to the sub-pixel SPix of blue(B), and the aperture portion 36I is formed in a position correspondingto a boundary between vertically adjacent pixels Pix in the figure. Theaperture portion 36H has a rectangular frame shape so as to adjust theelectrode edge length in the lateral direction and the electrode edgelength in the vertical direction independently of each other.

In the display device with a touch detection function 7, similar to thedisplay device with a touch detection function 1 according to theabove-described first embodiment, the electrode area per unit cell UC inthe touch detection electrode TDL3 is almost equal to the electrode areain the dummy electrode 37. Specifically, for example, the aperture widthWa of the aperture portion 36H and the aperture width Wb of the apertureportion 36I are adjusted so that these electrode areas are almost equalto each other.

Moreover, in the display device with a touch detection function 7,similar to the display devices with a touch detection function 5 and 5Baccording to the above-described second embodiment, the electrode edgelength in the vertical direction and the electrode edge length in thelateral direction are almost the same between the touch detectionelectrode TDL3 and the inter-detection-electrode region Rd. Inparticular, in the display device with a touch detection function 7,both the electrode edge length in the vertical direction and theelectrode edge length in the lateral direction may be independently set.

In the display device with a touch detection function 7, the touchdetection electrode TDL3 and the dummy electrode 37 are formed so thatthe electrode area per unit cell UC (pixel Pix) and the electrode edgelength in the vertical direction and in the lateral direction are almostthe same between the touch detection electrode TDL3 and theinter-detection-electrode region Rd. Therefore, the reflectance in thetouch detection electrode TDL3 and the reflectance in theinter-detection-electrode region Rd may be close to each other, andvisibility of the display screen may be improved.

Although example will be described in detail later with reference toFIG. 19, the electrode area ratio RS and the ratio of electrode edgelength RLE are close to 100% so that the reflectance ratio Rref is closeto 100%. Accordingly, it is confirmed that visibility of the displayscreen may be improved even when light enters from outside.

As described above, in the embodiment, the electrode area and theelectrode edge length in the vertical direction and in the lateraldirection are almost the same between the touch detection electrode andthe inter-detection-electrode region so that the reflectance in eachregion is almost equal to each other. Consequently, even when lightenters from outside, visibility of the display screen may be improved.Other effects are the same as in the above-described first embodiment.

5. EXAMPLE

The display devices with a touch detection function 1, 1B, 5, 5B, and 7which have been described as the first to third embodiments and themodifications thereof were experimentally manufactured, and theevaluations thereof were performed. The details will be described below.

FIG. 19 illustrates the display devices with a touch detection function1, 1B, 5, 5B, and 7 which were experimentally manufactured and theevaluation results thereof. The electrode area ratio RS and the ratio ofelectrode edge length RLE of each of the display devices with a touchdetection function 1, 1B, 5, 5B, and 7 experimentally manufactured wereset to various values as illustrated in FIG. 19. Note that the thicknessof each of the electrodes (the touch detection electrode and the dummyelectrode) was the same in the all display devices. The evaluation wasperformed for three evaluation items of a reflectance ratio Rref,reflection visibility, and transmission visibility. In the evaluation ofreflection visibility, the evaluation was performed to determine whethera touch detection electrode was visible under four conditions of “Sununder sunlight”, “Sky under sun light”, “Fluorescent lamp underfluorescent light”, and “Others under fluorescent light”. In this case,the condition of “Sun under sunlight” indicated a case where sunlightwas regularly reflected under the sunlight, the condition of “Sky undersunlight” indicated a case where a reflection direction was other than alight source (the sun)(for example, blue sky) under the sunlight, thecondition of “Fluorescent lamp under fluorescent light” indicated a casewhere fluorescent light was regularly reflected, and the condition of“Others under fluorescent light” indicated a case where a reflectiondirection was other than a light source (the fluorescent lamp) under thefluorescent light. In the evaluations under the conditions, a case wherethe touch detection electrode was not viewed from any directions wasregarded as “good”, and a case where the touch detection electrode wasviewed from all directions was regarded as “bad”. In addition, a casewhere the touch detection electrode was viewed from certain directions,but not viewed from the front of the display screen was regarded as“acceptable”. Moreover, in the evaluation of the transmissionvisibility, the evaluation was performed to determine whether the touchdetection electrode was visible when the display screen was viewed. Inthe evaluation, a case where the touch detection electrode was invisiblefrom any directions was regarded as “good”.

In the display devices with a touch detection function 1, 1B, 5, 5B, and7 described in the first to third embodiments, the touch detectionelectrode and the dummy electrode were formed so that the arrangementarea ratio of the touch detection electrode TDL was almost equal to thearrangement area ratio of the dummy electrodes in theinter-detection-electrode region Rd, and the electrode area ratio RS ofeach device was a value close to 100%. In addition, in the displaydevices with a touch detection function 5, 5B, and 7 according to thesecond and third embodiments, the touch detection electrode and thedummy electrode were formed so that the ratio of electrode edge lengthRLE was a value close to 100%. In particular, in the display device witha touch detection function 7 according to the third embodiment, theratio of electrode edge length RLE was a value extremely close to 100%.Accordingly, the reflectance ratio Rref was a value close to 100% in anydisplay device with a touch detection function. In the measurementresults of the reflection visibility, although a slight difference wasobserved, substantially good characteristics were obtained in anydisplay device with a touch detection function. Particularly, in thedisplay device with a touch detection function 7 according to the thirdembodiment, under the conditions of “Sun under sunlight” and“Fluorescent lamp under fluorescent light”, characteristics better thanthose of other display devices under other conditions were obtained.

As illustrated in FIG. 19, to obtain good reflection visibility, theelectrode area ratio RS was desirably set within a range of 98% to 102%.Preferably, the electrode area ratio RS was set within a range of 99% to101%.

Moreover, to confirm the effects of the display devices with a touchdetection function 1, 1B, 5, 5B, and 7, some display devices with atouch detection function (comparative examples 1 to 4) wereexperimentally manufactured. The display devices with a touch detectionfunction according to the comparative examples each has the apertureportions 36 same as those of the display device with a touch detectionfunction 1 (FIG. 8) according to the first embodiment. However, in thecomparative examples, different from the display device with a touchdetection function 1, as illustrated in FIG. 19, the width of theaperture portion 36 was equal to the distance between the adjacent dummyelectrodes 37, and therefore the electrode area ratio RS was not closeto 100%, and the reflectance ratio Rref was also not close to 100%.Accordingly, as the measurement results of the reflection visibilityaccording to the comparative examples, as illustrated in FIG. 19, thecharacteristics inferior to those of the display devices with a touchdetection function 1, 1B, 5, 5B, and 7 according to the above-describedembodiments were obtained.

Note that as for the transmission visibility, in any of the displaydevices with a touch detection function 1, 1B, 5, 5B, and 7 described inthe first to third embodiments and the display devices with a touchdetection function according to the comparative examples (comparativeexamples 1 to 4), favorable characteristics were obtained.

6. APPLICATION EXAMPLES

Next, application examples of the display devices with a touch detectionfunction described in the embodiments and the modifications will bedescribed with reference to FIG. 20 to FIG. 24G. The display device witha touch detection function of the above-described embodiments and thelike is applicable to electronic units in any fields, such as atelevision, a digital camera, a notebook personal computer, a portableterminal device such as a mobile phone, and a video camera. In otherwords, the display device with a touch detection function of theabove-described embodiments and the like is applicable to electronicunits in various fields for displaying a picture signal input fromoutside or a picture signal internally generated as an image or apicture.

Application Example 1

FIG. 20 illustrates an appearance of a television to which the displaydevice with a touch detection function of the above-describedembodiments and the like is applied. The television has, for example, apicture display screen section 510 including a front panel 511 and afilter glass 512. The picture display screen section 510 is configuredof the display device with a touch detection function according to theabove-described embodiments and the like.

Application Example 2

FIGS. 21A and 21B illustrate an appearance of a digital camera to whichthe display device with a touch detection function of theabove-described embodiments and the like is applied. The digital camerahas, for example, a light emitting section for a flash 521, a displaysection 522, a menu switch 523, and a shutter button 524. The displaysection 522 is configured of the display device with a touch detectionfunction according to the above-described embodiments and the like.

Application Example 3

FIG. 22 illustrates an appearance of a notebook personal computer towhich the display device with a touch detection function of theabove-described embodiments and the like is applied. The notebookpersonal computer has, for example, a main body 531, a keyboard 532 foroperation of inputting characters and the like, and a display section533 for displaying an image. The display section 533 is configured ofthe display device with a touch detection function according to theabove-described embodiments and the like.

Application Example 4

FIG. 23 illustrates an appearance of a video camera to which the displaydevice with a touch detection function of the above-describedembodiments and the like is applied. The video camera has, for example,a main body 541, a lens 542 for shooting an object provided on the frontside face of the main body 541, a shooting start/stop switch 543, and adisplay section 544. Also, the display section 544 is configured of thedisplay device with a touch detection function according to theabove-described embodiments and the like.

Application Example 5

FIGS. 24A to 24G illustrate an appearance of a mobile phone to which thedisplay device with a touch detection function of the above-describedembodiments and the like is applied. In the mobile phone, for example, atop-side enclosure 710 and a bottom-side enclosure 720 are joined by ajoint section (a hinge section) 730. The mobile phone has a display 740,a sub-display 750, a picture light 760, and a camera 770. The display740 or the sub-display 750 is configured of the display device with atouch detection function according to the above-described embodimentsand the like.

Hereinbefore, although the disclosure has been described with referringto the several embodiments, the modifications, the examples, and theapplication examples to the electronic units, the disclosure is notlimited thereto, and various modifications may be made.

For example, although in the above-described embodiments and the like,the light transmitting layer 33 is formed between the glass substrate 31and the touch detection electrode TDL, this is not limitative.Alternatively, the light transmitting layer 33 may be provided on thetouch detection electrode TDL as illustrated in FIG. 25

For example, although in the above-described embodiments and the like,the light transmitting layer 33 is provided, this is not limitative, andalternatively the light transmitting layer 33 may be omitted.

For example, although in the above-described embodiments and the like,the arrangement area ratio of the touch detection electrode and thearrangement area ratio of the dummy electrodes is almost equal to eachother, this is not limitative. Alternatively, the total length of allsides of the aperture portion per unit area and the total length of allsides of the dummy electrode per unit area may be almost equal to eachother. In this case, the reflectance in the touch detection electrodemay be almost equal to the reflectance in the dummy electrode, andtherefore, when light enters from outside, degradation in visibility ofthe display screen caused by the touch detection electrode may besuppressed.

For example, in the above-described embodiments and the like, thedisplay section with a touch detection function 10 is configured byintegrating the touch detection section 30 and the liquid crystaldisplay section 20 using a liquid crystal of various modes such as TN,VA, and ECB. Alternatively, the touch detection section may beintegrated with a liquid crystal display section using a liquid crystalof lateral-electric-field mode such as FFS (fringe field switching) andIPS (in-plane switching). For example, in a case where a liquid crystalin the lateral-electric-field mode is used, a display section with atouch detection function 90 may be configured as illustrated in FIG. 26.FIG. 26 illustrates an example of a cross-sectional configuration of arelative part in the display section with a touch detection function 90,and illustrates a state where a liquid crystal layer 6B is sandwichedbetween a pixel substrate 2B and a facing substrate 3B. Since names,functions, and the like of other parts are the same as in the case ofFIG.5, the description thereof is omitted. In the example, unlike thecase of FIG. 5, the drive electrodes COML commonly used for display andfor touch detection are formed directly on the TFT substrate 21, andconfigure a part of the pixel substrate 2B. The pixel electrodes 22 arearranged above the drive electrodes COML through the insulating layer23. In this case, all dielectric bodies including the liquid crystallayer 6B, which are arranged between the drive electrodes COML and thetouch detection electrode TDL, contribute to the formation of thecapacitance element C1.

For example, although in the above-described embodiments and the like,the liquid crystal display section 20 and the touch detection section 30are integrated, this is not limitative. Alternatively, a touch detectionsection (a touch detection device) may be configured separately from aliquid crystal display section. In this case, in the touch detectionsection, the arrangement area ratio of the touch detection electrode TDLis almost equal to the arrangement area ratio of the dummy electrodes inthe inter-detection-electrode region Rd so that the reflectance inrespective regions are almost equal to each other. Accordingly, when thetouch detection section is mounted on the display device, visibility ofthe display screen may be improved.

The present application contains subject matter related to thatdisclosed in Japanese Priority Patent Application JP 2010-186197 filedin the Japan Patent Office on Aug. 23, 2010, the entire content of whichis hereby incorporated by reference.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalent thereof.

What is claimed is:
 1. A display device with a touch detection function,comprising: a plurality of display elements; a plurality of touchdetection electrodes arranged in parallel and extending along onedirection; and a plurality of dummy electrodes disposed in aninter-detection electrode-region that is a region between adjacent touchdetection electrodes, wherein, each of the display elements configures adisplay pixel, the inter-detection-electrode region, including the dummyelectrodes, is divided into a plurality of dummy electrode blocks by aplurality of gaps including (a) a first gap, which extends in a firstdirection that is an arrangement direction of the display elements, and(b) a second gap, which extends in a second direction intersecting withthe first direction, and the touch detection electrodes and the dummyelectrodes are arranged in both of a display region and a frame region,the frame region being outside the display region.
 2. The display devicewith a touch detection function according to claim 1, wherein: the touchdetection electrodes and the dummy electrodes are arranged in a samelayer, and the dummy electrodes are uniformly arranged in both of thedisplay region and the frame region.
 3. The display device with a touchdetection function according to claim 1, wherein: the dummy electrodesare configured of a plurality of dummy electrode unit cells, each of thedummy electrode unit cells is arranged in a position corresponding to arespective display element, and a size of each of the dummy electrodeunit cells corresponds to a size of the display pixel.
 4. The displaydevice with a touch detection function according to claim 1, wherein ashape of each of the dummy electrode blocks in the display region issubstantially a same as a shape of each of the dummy electrode blocks inthe frame region.
 5. The display device with a touch detection functionaccording to claim 1, wherein: the touch detection electrodes are formedwith a predetermined electrode pattern including a plurality of apertureportions, and an open area ratio of the touch detection electrodes inthe predetermined electrode pattern is substantially equal to an openarea ratio of the dummy electrodes in the inter-detection-electroderegion.
 6. The display device with a touch detection function accordingto claim 1, wherein: the touch detection electrodes are formed with apredetermined electrode pattern including a plurality of apertureportions, the aperture portions include first aperture portions eachhaving longitudinal sides in the first direction and second apertureportions each having longitudinal sides in the second direction, thedisplay elements include at least a red display element, a green displayelement, and a blue display element, and the second aperture portionsand the second gaps in the dummy electrodes are disposed in positionscorresponding to individual blue display elements.
 7. The display devicewith a touch detection function according to claim 6, wherein: pairs ofthe second aperture portions are disposed in positions corresponding tothe individual blue display elements, and the pair of the secondaperture portions are parallel to each other.
 8. The display device witha touch detection function according to claim 6, wherein the secondaperture portions each having a shape of a letter “I” are disposed inpositions corresponding to the individual blue display elements.
 9. Thedisplay device with a touch detection function according to claim 6,wherein the second aperture portions having a shape of a closed loop aredisposed in positions corresponding to the individual blue displayelements.
 10. The display device with a touch detection functionaccording to claim 1, further comprising a plurality of scan lines,wherein: the touch detection electrodes are formed with a predeterminedelectrode pattern including a plurality of aperture portions, theaperture portions include first aperture portions each havinglongitudinal sides in the first direction, and the first apertures andthe first gaps are disposed in positions corresponding to individualscan lines.
 11. The display device with a touch detection functionaccording to claim 1, wherein: the touch detection electrodes are formedwith a predetermined electrode pattern including a plurality of apertureportions, and a plurality of dummy apertures are disposed in theindividual dummy electrode blocks.